1. Field of the Invention
The present invention relates to a hydraulic servo door closer which has different translation ratios as a function of travel and direction. The different translation ratios thereby significantly improve the ease of operation of a door equipped with the present invention.
The present invention preferably includes a door piston which is guided in a housing, whereby the drive shaft of the door piston can be connected to a door by means of a linkage. There can also be an energy storage mechanism in the form of a spring, which spring can store energy during the opening of the door and can release it again for a subsequent automatic closing process.
The servo door closer can have at least two different translation ratios, as a function of direction and of the distance travelled, whereby simultaneously, the fixed or solid coupling between the opening force and the closing force is preferably neutralized by the fact that, between the spring and the door piston, there can be at least one hydraulic transmission which can include at least one spring piston, the door piston and an inner piston inside the door piston, as well as the chamber which is defined by this inner piston and a housing which surrounds the inner piston.
During the closing phase, the door piston can be moved away from the spring piston. This movement is preferably achieved because the damping medium can penetrate between the door piston and the spring piston via a pocket which can be located in the housing.
2. Background Information
A process and a device for controlling the force of a closing device is described in German Patent No. 35 35 506 A1. The door is connected to the door frame by means of a closing device, which closing device is in the form of a door closer, and by means of linkage arms which are capable of pivoting in relation to one another. The control system for the different force required for the opening and subsequent automatic closing of the door is modified by the displacement of the end of the linkage which is at some distance from the door closing device, to appropriately modify the torque exerted by the closing device on the door in separate phases of the opening and closing of the door. This known system is a device which requires the input of outside energy, i.e. there is an electric motor which displaces a bar or translating part and simultaneously defines the position of the bar in a guide element. The motor control is accordingly set as a function of the desired opening angle.
U.S. Pat. No. 4,979,261 discloses a door closer with a variable coupling position. As a result of a gear wheel which is fastened to the closer shaft, which gear wheel rolls along the door, the engagement point of the linkage and thus of the entire moment curve is changed automatically. As a result of the use of the mechanical means described above, there is a reduction of the opening force and a simultaneous increase of the closing force.
U.S. Pat. No. 3,818,637 discloses a device which makes possible the rapid opening of a door.
A device which uses a linear force to open a door is disclosed in U.S. Pat. No. 4,231,192. In this device, a corresponding lever system is used in connection with an outside energy source in the form of an electric current to achieve an approximately linear curve of the force on the door as a function of the opening angle.
A door closer which works with two pistons is described in U.S. Pat. No. 4,040,144. This system also works with outside energy in the form of air.
U.S. Pat. No. 4,419,786 describes a system by means of which the force required to open a door in normal door opening situations is reduced. In this system, a door closer is used. As a result of the displacement of the far end of the linkage which is connected to the door closer, the force ratio is changed, below a defined opening angle, by the use of additional spring forces and a hydraulic or pneumatic control system. It is thereby possible to change the torque exerted on the door by the door closer by means of the articulated linkage system. This system is very complicated, and cannot be used universally or be adapted for all different types of operation.
A device in the form of a door closer which is described in Swedish Patent 469 342 consists of a housing in which two pistons are arranged so that they can move. There are also two springs, with each spring corresponding directly to a respective piston, wherein the two springs act in the same direction on the pistons. One piston is connected to a piston rod, the rear end of which piston rod is located in a sealed manner in a central boring in the other piston. The two pistons have different diameters. The fluid flow of the damping medium through the piston is controlled by means of various channels in connection with valves. As a result of these measures, the force required to open the door is small, although a large force is still provided for the final phase of the closing process.
To reduce the opening moment, German Laid Open Patent Application No. 32 34 319 discloses a device in which the required greater closing force is applied by means of an outside energy source to provide a spring bias. In this known device, the additional spring bias can be generated both by an electric motor and by a piston with a hydraulic circuit which is powered by outside energy.